Copolymers of diglycidyl ether terminated polysiloxane compounds and non-aromatic polyamines

ABSTRACT

Copolymers of diglycidyl ether terminated polysiloxane compounds and non-aromatic polyamines are used in the preparation of dielectric materials for electroless metal plating. The copolymers may be used in the manufacture of printed circuit boards such as in cleaning and conditioning through-holes prior to electroless metallization.

FIELD OF THE INVENTION

The present invention is directed to copolymers of diglycidyl etherterminated polysiloxane compounds and non-aromatic polyamines. Morespecifically, the present invention is directed to copolymers ofdiglycidyl ether terminated polysiloxane compounds and non-aromaticpolyamines for cleaning and conditioning dielectrics prior toelectroless metallization.

BACKGROUND OF THE INVENTION

The electronics industry desires a metallized coating on dielectricmaterials for functional and aesthetic purposes. A particularlyimportant technological area where the techniques of metallization ofdielectric materials have found applicability is in the manufacture ofprinted circuit boards, where metallization is used to providepatterned, conductive circuitry on substrates with dielectric materials.Metallization of dielectric materials may come into play at a number ofsteps in the overall process of printed circuit board manufacture. Onearea of substantial importance is the electroless metallization ofthrough-holes.

Typically, printed circuit boards are planar and have printed circuitson both sides. The boards may be multi-layer and contain laminates ofdielectric substrates and conductive metal such as copper, where one ormore parallel inner layers of conductive metal are separated bydielectric substrates. Exposed outer sides of the laminate containprinted circuit patterns as in double-sided boards and the innerconductive layers may themselves comprise circuit patterns. Indouble-sided and multi-layer printed circuit boards, it is necessary toprovide conductive interconnection between or among the various layersor sides of the boards. This is achieved by providing metallized,conductive through-holes in the boards communicating with the sides andlayers requiring electrical interconnection. Typically the method forproviding conductive through-holes is by electroless deposition of metalon the dielectric surfaces of the through-holes drilled or punchedthrough the boards.

Electroless deposition of metal on dielectric surfaces typicallyinvolves applying a material which is catalytic to the electrolessplating process to the dielectric surfaces. This is known as“activation” of the through-hole surfaces. Such catalytic material maybe a noble metal such as palladium. When plating through-holes withcopper, the catalyst is often a colloidal solution of palladium and tincompounds. The tin functions as a protective colloid for the catalyticpalladium. In many cases the activation is followed by an “acceleration”step which serves in some manner to expose or increase exposure of theactive catalytic species.

Notwithstanding the fact that the topography of the through-holesurfaces can be such, e.g., roughened or pitted, as to promote adhesionof catalysts for electroelss metal deposition, the properties of thedielectric substrate material may still lead to poor adhesion. A primaryexample of this is found in the glass-filled epoxy resins which are usedextensively in the printed circuit board industry as the dielectricsubstrate. Poor palladium catalyst adsorption leads to incomplete or toothin coverage of subsequently electrolessly plated copper in thethrough-holes. A possible explanation for this is that the glass fibershave a highly negative surface charge and do not attract the typicaltin-palladium catalyst which also carries a negative charge. However,the problem of poor metal coverage in through-holes is not restricted toglass-containing dielectric substrates and also occurs in substrateswith any number of a variety of non-glass-containing, dielectricmaterials used as circuit board substrates. Complete metal coverage ofthrough-holes is important.

In response to the problem of poor metal coverage of epoxy-glasssubstrates, the printed circuit board industry addressed the problem byusing a process known as “conditioning” prior to application of thecatalyst. Conditioning agents are compounds or mixtures of compoundswhich function to improve the adsorption of activating material onsubstrate surfaces to improve subsequent electroless metal platingquality. The exposed through-hole surfaces are coated with theconditioning agents and the catalytic species builds up on the coatingand adheres to the surface.

Although conditioning through-hole walls results in improved metalcoverage in contrast to non-conditioned through-holes, coverage ofthrough-holes in glass-epoxy substrates as well as other types ofdielectric substrates with many current conditioning agents does notalways meet industry standards. Accordingly, there is still a need foran improved conditioner for electroless metallization of dielectricsubstrates.

SUMMARY OF THE INVENTION

Copolymers include a reaction product of one or more diglycidyl etherterminated polysiloxane compounds and one or more non-aromaticpolyamines.

Compositions include a reaction product of one or more diglycidyl etherterminated polysiloxane compounds and one or more non-aromaticpolyamines; and one or more organic solvents.

Methods include providing a substrate comprising a dielectric;contacting the substrate with a composition comprising a reactionproduct of one or more diglycidyl ether terminated polysiloxanecompounds and one or more non-aromatic polyamines; applying a catalystto the substrate; and electrolessly metal plating the substrate.

The conditioner compositions and methods provide good metal coverage ofdielectric materials. The copolymers and methods also may reduce theundesirable ring of pearls or voids often found on incompletely metalplated though-hole walls of dielectric materials used in the electronicsindustry. Such ring of pearls may result in defects in electronicdevices.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows backlight measurement comparisons of electroless copperplating of through-holes of various copper clad test panels treated withconditioners containing 3-aminopropyltriethoxysilane, and a reactionproduct of tetraethylenepentamine and diglycidyl ether terminatedpoly(dimethylsiloxane);

FIG. 2 shows backlight measurement comparisons of electroless copperplating of through-holes of various copper clad test panels treated withseven different conditioners of reaction products of polysiloxanediglycidyl ethers and non-aromatic polyamines.

DETAILED DESCRIPTION OF THE INVENTION

As used throughout this specification, the abbreviations given belowhave the following meanings, unless the context clearly indicatesotherwise: g=gram; mg=milligram; mL=milliliter; L=liter; ppm=parts permillion; M=molar; ° C.=degrees Centigrade; g/L=grams per liter;DI=deionized; Mw=weight average molecular weight; Mn=number averagemolecular weight; wt %=percent by weight; T_(g)=glass transitiontemperature; EO/PO=ethylene oxide/propylene oxide;APTES=3-aminopropyltriethoxysilane; ROP=ring of pearls; SROP=slight ringof pearls; sev-ROP=severe ring of pearls; LG=looks good; R=rough;SR=slightly rough; VSR=very slightly rough; TETA=triethylenetetramineand TEPA=tetraethylenepentamine.

The term “monomer” or “monomeric” means a single molecule or compoundwhich may combine with one or more of the same, similar or dissimilarmolecules. The term “copolymer” means a polymer produced by thesimultaneous polymerization of two or more dissimilar monomers. The term“polyamine” means a compound which includes at least two amine groups.The term “alkylamine” includes, but is not limited to: linear andbranched, cyclic and acyclic polyalkylamines, including but not limitedto ethylenediamine, diethylenetriamine, triethylenetetramine,tetraethylenepentamine, pentaethylenehexamine, and piperazine. The term“moiety” means a part of a molecule which may include whole functionalgroups or parts of functional groups. The terms “plating” and“deposition” are used interchangeably throughout this specification. Theterm “a” and “an” may refer to both the singular and the plural. Allamounts are percent by weight, unless otherwise noted. All numericalranges are inclusive and combinable in any order except where it islogical that such numerical ranges are constrained to add up to 100%.

Copolymers include a reaction product of one or more diglycidyl etherterminated polysiloxane compounds and one or more non-aromaticpolyamines. The copolymers may be used in conditioner compositions inthe preparation of dielectric materials for adsorbing a catalyst forelectroless metallization of the dielectric materials. The conditionercompositions provide good metal coverage of dielectric materialsincluding walls of through-holes and vias such as are found in printedcircuit boards. The conditioner compositions may also reduce theundesirable “ring of pearls” on the walls of through-holes and vias. Thering of pearls is sections of the through-hole or via where metal is notdeposited during the electroless metal plating process. They are voidswhich circumvallate the walls of through-holes and vias and maycompromise the performance of electronic devices which include theprinted circuit boards.

Diglycidyl ether terminated polysiloxane compounds include, but are notlimited to compounds having a general formula:

where R₁, R₂, R₃, R₄, R₅ and R₆ may be the same or different and arechosen from hydrogen; linear or branched, substituted or unsubstituted(C₁-C₆)alkyl; m is an integer of 1 to 6, and n is an integer of 1 to 20.Preferably R₁, R₂, R₃, R₄, R₅ and R₆ are the same or different and arechosen from linear or branched, substituted or unsubstituted(C₁-C₆)alkyl. More preferably R₁, R₂, R₃, R₄, R₅ and R₆ are the same ordifferent and are chosen from unsubstituted, linear (C₁-C₃)alkyl.Preferably m is an integer of 1 to 3 and n is an integer of 1 to 10.Substituent groups include, but are not limited to: hydroxyl; linear orbranched hydroxy(C₁-C₃)alkyl; and linear or branched (C₁-C₅)alkoxy. Suchdiglycidyl ether terminated polysiloxane compounds may have Mw from 200to 7000 and/or Mn from 200 to 7000. Diglycidyl ether terminatedpolysiloxane compounds may be made according to methods disclosed in theliterature, known in the art or may be commercially obtained fromsuppliers such as Gelest, Inc.

Non-aromatic polyamines include aliphatic and alicyclic polyamines. Thenon-aromatic polyamines include at least two amine moieties which mayreact with the diglycidyl ether terminated polysiloxane compounds. Theamine moieties which react with the diglycidyl ether terminatedpolysiloxane compounds may be primary or secondary amine moieties.Preferably such non-aromatic polyamines include, but are not limited to:compounds having a general formula:

where R₇, R₈ and R₉ are independently chosen from hydrogen; linear orbranched, substituted or unsubstituted (C₁-C₁₀)alkylamine; linear orbranched, substituted or unsubstituted (C₁-C₁₀)alkyl; or a moiety havingthe general formula:

where R₁₀ and R₁₁ are independently chosen from hydrogen; linear orbranched, substituted or unsubstituted (C₁-C₁₀)alkyl; linear orbranched, substituted or unsubstituted (C₁-C₁₀)alkylamine; and with theproviso that if the nitrogen atoms in compounds II and III are tertiary,at least one of R₇, R₈, and R₉ include substituent groups with at leasttwo primary nitrogen atoms, secondary nitrogen atoms, or a combinationof primary and secondary nitrogen atoms; R₁₂ through R₁₅ areindependently chosen from hydrogen; linear or branched, substituted orunsubstituted (C₁-C₁₀)alkyl; and linear or branched, substituted orunsubstituted (C₁-C₁₀)alkylamine; and q, r and t may be the same ordifferent and are integers of 1 to 10. Preferably R₁₀ through R₁₅ arehydrogen. Substituent groups include, but are not limited to: hydroxyl;hydroxy(C₁-C₃)alkyl; (C₁-C₅)alkoxy; and linear or branched(C₁-C₁₀)alkylamine. Preferably at least one of R₇, R₈ and R₉ is formula(IV). More preferably, two of R₇, R₈ and R₉ are formula (IV) and theremainder hydrogen. Preferably q, r and t are the same or different andare 1 to 5, more preferably from 1 to 3. Such non-aromatic polyaminesmay be prepared from the literature, methods known in the art orobtained commercially such as from Sigma Aldrich.

There is no limitation on the methods which may be used to prepare thereaction products. Preferably, one or more non-aromatic amines aresolubilized in one or more organic solvents with stiffing at roomtemperature. Such organic solvents, preferably, are water miscible andinclude, but are not limited to: acetonitrile and water misciblealcohols such as isopropanol, ethanol and methanol. One or morediglycidyl ether terminated polysiloxane compounds is then added to thesolution of the one or more non-aromatic amines with heating to raisethe temperature of the solution from room temperature to 90° C. to 110°C. The solution is heated for 3 hours to 8 hours and then left to stirat room temperature overnight. Molar ratios of one or more non-aromaticamines to one or more diglycidyl ether terminated polysiloxane compoundsin the reaction mixture may range from 4:1 to 1:1.

The reaction products may be included in conditioner compositions inamounts of 0.1 g/L to 15 g/L, preferably from 1 g/L to 5 g/L. Thecompositions may include one or more additives such as surfactants,complexing agents, wetting agents and pH adjusting agents. Surfactantsinclude, but are not limited to: non-ionic surfactants and cationicsurfactants. One or more surfactants may be included in conventionalamounts. Preferably, they are included in amounts of 0.1 g/L to 20 g/L,more preferably from 0.5 g/L to 5 g/L. Examples of non-ionic surfactantsare polyglycol ethers, ethylene oxide/propylene oxide copolymers,polyoxyethylene octylphenyl ethers, polyoxyethylene nonylphenyl ethers,and ethoxylated linear alcohols. An example of a cationic surfactant isquaternized polyvinylimidazole. One or more complexing agents may beincluded in conventional amounts. Preferably, they are included inamounts of 0.1 g/L to 5 g/L, more preferably, from 0.1 g/L to 1.5 g/L.Complexing agents include, but are not limited to:ethylenediaminetetraacetic acid; N-(2-hydroxyethyl)iminodiacetic acid;iminodiacetic acid; diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid;N-(5-(3-maleimidopropylamido)-1-carboxy-pentyl)iminodiacetic acid;nitrilotriacetic acid; N-(5-amino-1-carboxypentyl)iminodiacetic acid;ethylenediaminedi(o-hydroxyphenylacetic) acid; andN,N′-bis(2-hydroxybenzyl)ethylenediamine-N,N′-diacetic acid. One or morewetting agents may be included in conventional amounts. Preferably, theyare included in 0.5 g/L to 8 g/L amounts, more preferably from 2 g/L to5 g/L. Wetting agents include but are not limited to: alkanolamines suchas monoethanolamine; triethanolamine; triisopropanolamine;N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylene diamine; amino-2-propanol;and bis(2-hydroxypropyl)amine. pH adjusting agents include, but are notlimited to: alkali metal hydroxides such as sodium hydroxide andpotassium hydroxide. One or more of inorganic acids and organic acidsmay be used to adjust the pH. Inorganic acids include, but are notlimited to: sulfuric acid, hydrochloric acid, nitric acid and phosphoricacid. Organic acids include, but are not limited to: monocarboxylicacids such as acetic acid and polycarboxylic acids such as citric acid.pH adjusting agent are included in amounts to maintain a pH of greaterthan 7, preferably from 8 to 12, more preferably from 8.5 to 11. Theconditioner compositions may be raised to their desired volume level andcomponent concentrations using one or more of water and water miscibleorganic solvents. Preferably, the conditioner compositions consistessentially of one or more reactions products, one or more watermiscible organic solvents, one or more surfactants, one or morecomplexing agents, one or more wetting agents, one or more pH adjustingagents and water.

The conditioner compositions may be used to condition dielectricmaterials including through-hole and via walls for the reception of manyconventional catalysts used for electroless metal plating including butnot limited to: conventional tin-palladium colloidal catalysts and ioniccatalysts. Preferably, the conditioner compositions are used to preparedielectric materials including through-hole and via walls for thereception of ionic catalysts. Such ionic catalysts preferably areaqueous alkaline non-colloidal solutions of complexes of metal ions andone or more complexing agents. Preferably, aqueous alkaline ioniccatalysts are free of tin, tin ions, antioxidants and halogens. The pHrange of the aqueous alkaline ionic catalyst solutions is from 8.5 andgreater, preferably from 9 and greater, more preferably from 9 to 13,most preferably from 9 to 12. In general, the catalytic metal ions arenot reduced to their metal state until after the catalyst is applied tothe conditioned dielectric material. Conventional reducing agents may beused. Such reducing agents include, but are not limited to:dimethylamine borane, sodium borohydride, ascorbic acid, iso-ascorbicacid, sodium hypophosphite, hydrazine hydrate, formic acid andformaldehyde. Preferably the reducing agent is sodium hypophosphite ordimethylamine borane. Reducing agents are included in amounts to reducesubstantially all of the metal ions to metal. Such amounts are generallyconventional amounts and are well known by those of skill in the art.

Metal ions may be provided by conventional metal salts. Typically suchmetal salts are included in the catalyst solutions to provide metal ionsin amounts of 20 ppm to 2000 ppm, preferably from 25 ppm to 500 ppm.Metal ions include, but are not limited to: silver, gold, platinum,palladium, copper, cobalt and nickel ions. Preferably, the metal ionsare chosen from silver and palladium ions. Most preferably the metalions are palladium ions. Metal ions may be provided by usingconventional water soluble metal salts which are well known in the artand may be found in the literature.

In general, the amount of complexing compounds and one or more metalions included in the aqueous alkaline ionic catalyst solutions are suchthat a molar ratio of complexing compounds to metal ions is from 1:1 to4:1, preferably from 1:1 to 2:1. Complexing agents include, but are notlimited to: pyrazine derivatives and pyrimidine derivatives. Pyrazinederivatives include, but are not limited to: 2,6-dimethylpyrazine,2,3-dimethylpyrazine, 2,5-dimethylpyrazine, 2,3,5-trimethylpyrazine,2-acetylpyrazine, aminopyrazine, ethylpyrazine, methoxypyrazine, and2-(2′-hydroxyethyl)pyrazine. Pyrimidine derivatives include, but are notlimited to: barbituric acid, orotic acid, thymine, 2-aminopyrimidine,6-hydroxy-2,4-dimethylpyrimidine, 6-methyluracil, 2-hydroxypyrimidine,4,6-dichloropyrimidine, 2,4-dimethoxypyrimidine,2-amino-4,6-dimethylpyrimidine, 2-hydroxy-4,6-dimethylpyrimidine and6-methylisocytosine.

The conditioner compositions may be used to prepare various dielectricmaterials for catalyst reception for electroless metal plating. Thedielectric materials may be included on various substrates such assemiconductors, metal-clad and unclad substrates such as printed circuitboards with a plurality of through-holes, vias or combinations thereof.Such metal-clad and unclad printed circuit boards may includethermosetting resins, thermoplastic resins and combinations thereof,including fiber, such as fiberglass, and impregnated embodiments of theforegoing. Preferably the substrate is a metal-clad printed circuit orwiring board with a plurality of through-holes, vias or combinationsthereof.

The conditioner compositions may be used in both horizontal and verticalprocesses of manufacturing printed circuit boards. The conditionercompositions may be used with conventional aqueous alkaline electrolessmetal plating baths. While it is envisioned that the conditioners may beused in methods for electrolessly plating any metal which may beelectrolessly plated, preferably, the metal is chosen from copper,copper alloys, nickel or nickel alloys. More preferably the metal ischosen from copper and copper alloys, most preferably copper is themetal. Conventional metal electroless plating baths may be used. Variouselectroless baths are well known in the art and disclosed in theliterature. Examples of commercially available electroless copperplating baths are CIRCUPOSIT™ 4500 and CIRCUPOSIT™ 880 ElectrolessCopper baths (available from Dow Advanced Materials, Marlborough,Mass.).

Conventional steps for electroless metal plating a substrate withdielectric material may be used with the conditioner composition;however, the aqueous alkaline ionic catalysts do not require anacceleration step where tin is stripped to expose the palladium metalfor electroless plating when a colloidal tin-palladium catalyst is used.Preferably, the conditioner compositions are applied to the substratewith the dielectric material at temperatures from room temperature to90° C., preferably from 30° C. to 80° C. The conditioner may be appliedto the substrate by immersing the substrate in the conditioner or theconditioner may be sprayed on the substrate. The conditioner may be incontact with the substrate for 30 seconds to 180 seconds before thesubstrate is optionally rinsed with water. A catalyst is applied to theconditioned substrate to be electrolessly plated with a metal. If thecatalyst is an ionic type catalyst a reducing agent is subsequentlyapplied to the substrate, otherwise, as in the case of a tin-palladiumcatalyst, the catalytic metal ion is already reduced to the metal stateduring catalyst application. Electroless metal plating parameters, suchas temperature and time may be conventional. The pH of the electrolessmetal plating bath is typically alkaline. Conventional substratepreparation methods, such as cleaning or degreasing the substratesurface, roughening or micro-roughening the surface, etching ormicro-etching the substrate, solvent swell applications, desmearingthrough-holes and various rinse and anti-tarnish treatments may be used.Such methods and formulations are well known in the art and disclosed inthe literature.

Preferably, the substrate to be metal plated is a metal-clad substratewith dielectric material and a plurality of through-holes, vias orcombinations thereof such as a printed circuit board. The boards may berinsed with water and cleaned and degreased followed by desmearing thethrough-hole walls and vias. Typically prepping or softening thedielectric or desmearing of the through-holes and vias begins withapplication of a solvent swell. Typically, rinsing the substrate withwater is done between each step.

Any conventional solvent swell may be used. The specific type may varydepending on the type of dielectric material. Minor experimentation maybe done to determine which solvent swell is suitable for a particulardielectric material. The T_(g) of the dielectric may determine the typeof solvent swell to be used. Solvent swells include, but are not limitedto: glycol ethers and their associated ether acetates. Conventionalamounts of glycol ethers and their associated ether acetates may beused. Examples of commercially available solvent swells are CIRCUPOSIT™MLB Conditioner 211 solution, CIRCUPOSIT™ Hole Prep 3303 and CIRCUPOSIT™Hole Prep 4120 solutions (available from Dow Advanced Materials).

After the solvent swell, a promoter may be applied. Conventionalpromoters may be used. Such promoters include sulfuric acid, chromicacid, alkaline permanganate or plasma etching. Typically alkalinepermanganate is used as the promoter. Examples of commercially availablepromoters are CIRCUPOSIT™ Promoter 4130 and CIRCUPOSIT™ MLB Promoter3308 solutions (available from Dow Advanced Materials). Optionally, thesubstrate is rinsed with water.

A neutralizer may then be applied to neutralize any residues left by thepromoter. Conventional neutralizers may be used. Typically theneutralizer is an aqueous acidic solution containing one or more aminesor a solution of 3 wt % hydrogen peroxide and 3 wt % sulfuric acid. Anexample of a commercially available neutralizer is CIRCUPOSIT™ MLBNeutralizer 216-5 solution (available from Dow Advanced Materials).Optionally, the substrate and through-holes are rinsed with water andthen dried.

After neutralization, a conditioner composition with one or morereaction products of one or more diglycidyl ether terminatedpolysiloxane compounds and one or more non-aromatic polyamines asdescribed above is applied to the substrate. Optionally, the substrateis rinsed with water.

Conditioning may be followed by micro-etching. Conventionalmicro-etching compositions may be used. Micro-etching is designed toprovide a micro-roughened metal surface on exposed metal (e.g. innerlayers and surface) to enhance subsequent adhesion of plated electrolessmetal and later electroplate. Micro-etches include, but are not limitedto: 60 g/L to 120 g/L sodium persulfate or sodium or potassiumoxymonopersulfate and sulfuric acid (2%) mixture, or generic sulfuricacid/hydrogen peroxide. Examples of commercially available micro-etchingcompositions are CIRCUPOSIT™ Etch 3330 solution and PREPOSIT™ 748 Etchsolution, both available from Dow Advanced Materials. Optionally, thesubstrate is rinsed with water.

Optionally, a pre-dip may then be applied to the micro-etched substrate.Pre-dip components include but are not limited to: organic salts such assodium potassium tartrate, sodium carbonate or sodium citrate, nitricacid, sulfuric acid or an acidic solution of 25 g/L to 75 g/L sodiumsulfate.

The catalyst is then applied to the substrate. Application may be doneby conventional methods used in the art, such as immersing the substratein a solution of the catalyst or by spraying using conventionalapparatus. Catalyst dwell time may range from 1 minute to 10 minutes,typically from 2 minutes to 8 minutes for vertical equipment and for 25seconds to 120 seconds for horizontal equipment. The catalysts may beapplied at temperatures from room temperature to 80° C., typically from30° C. to 60° C. The substrate optionally may be rinsed with water afterapplication of the catalyst.

If the catalyst is an ionic catalyst where the catalytic metal ions havenot yet been reduced to their metal state, a reducing solution is thenapplied to the substrate to reduce the metal ions of the catalyst tometal. The reducing solution may be applied by immersing the substrateinto the reducing solution or spraying the reducing solution on thesubstrate. The temperature of the solution may range from roomtemperature to 65° C., typically from 30° C. to 55° C. Contact timebetween the reducing solution and the catalyzed substrate may range from30 seconds to 5 minutes before application of the electroless metalplating bath.

The substrate is then electrolessly plated with metal, such as copper,copper alloy, nickel or nickel alloy using an electroless bath.Preferably copper is plated on the walls of the through-holes and viasof the substrate. Plating times and temperatures may be conventional.Typically metal deposition is done at room temperature to 80° C., moretypically from 30° C. to 60° C. The substrate may be immersed in theelectroless plating bath or the electroless bath may be sprayed on thesubstrate. Typically, electroless plating may be done for 5 seconds to30 minutes; however, plating times may vary depending on the thicknessof the metal desired. Plating is preferably done in an alkalineenvironment to prevent undesired corrosion of any metal cladding on thesubstrate. Typically the pH of the plating solution is 8 and higher,preferably the pH is 8.5 and greater, more preferably the pH is from 9to 13, most preferably the pH is from 9 to 12.

Optionally anti-tarnish may be applied to the metal. Conventionalanti-tarnish compositions may be used. An example of anti-tarnish isANTI TARNISH™ 7130 solution (available from Dow Advanced Materials). Thesubstrate may optionally be rinsed with water and then dried.

Further processing may include conventional processing by photoimagingand further metal deposition on the substrates such as electrolyticmetal deposition of, for example, copper, copper alloys, tin and tinalloys.

The conditioner compositions and methods provide good metal coverage ofdielectric materials and through-hole walls and vias. The copolymers andmethods also may reduce the undesirable ring of pearls typically foundon the walls of incompletely metal plated through-holes which may resultin defects in electronic devices in which the substrates are used.

The following examples are not intended to limit the scope of theinvention but to further illustrate the invention.

Example 1

Copolymer 2 was prepared by dissolving technical gradetetraethylenepentamine (11.86 g, 0.062 mol) in 20 mL isopropanol in a100 mL round-bottom, three-neck flask equipped with condenser,thermometer, and stir bar at room temperature. Diglycidyl etherterminated poly(dimethylsiloxane) (Mn ˜0.800, 25.04 g, 0.031 mol) wasadded dropwise to the solution, and the vial containing the diglycidylether terminated poly(dimethylsiloxane) was rinsed with 2 mLisopropanol. The heating bath temperature was increased to 96° C. Theresulting mixture was heated for 4 hours and then the reaction was leftto stir at room temperature overnight. The reaction mixture was rinsedwith water into a polyethylene bottle for storage. The molar ratio oftetraethylenepentamine to diglycidyl ether terminatedpoly(dimethylsiloxane) was determined to be 2:1 based on monomer molarratios.

Copolymers 1 and 3-8 were prepared substantially according to the methodby which copolymer 2 was prepared. TETA and TEPA DOW amine mixtures wereused as is, with molecular weights assumed to be those oftriethylenetetramine and tetraethylenepentamine, respectively.

Co- poly- mer Monomer 1 (M₁) Monomer 2 (M₂) 1

Diethylenetriamine

Mn 800 Diglycidyl ether terminated poly(dimethylsiloxane) 2

Tetraethylenepentamine Mn 800 Diglycidyl ether terminatedpoly(dimethylsiloxane) 3

Mn 800 Diglycidyl ether terminated poly(dimethylsiloxane)

TETA Dow Amine Mix 4

Mn 800 Diglycidyl ether terminated poly(dimethylsiloxane)

TEPA Dow Amine Mix 5

Triethylenetramine Mn 800 Diglycidyl ether terminatedpoly(dimethylsiloxane) 6

Pentaethylenehexamine Mn 800 Diglycidyl ether terminatedpoly(dimethylsiloxane) 7

Tetraethylenepentamine Mn 363 Diglycidyl ether terminatedpoly(dimethylsiloxane) 8

Tetraethylenepentamine Mn 500-600 Diglycidyl ether terminatedpoly(dimethylsiloxane)

Example 2

Comparisons were done of electroless copper coverage on four-layer oreight-layer copper-clad test panels with a plurality of through-holesusing three different conditioners. The panels were constructed fromTUC-662, SY-1141, SY-1000-2, IT-158, IT-180 and NPG-150 laminates.TUC-662 was obtained from Taiwan Union Technology, SY-1141 and SY-1000-2were obtained from Shengyi. The IT-158 and IT-180 are from ITEQ Corp.and the NPG-150 is from NanYa. Each panel was 5 cm×12 cm.

Aqueous conditioner solutions were prepared to include 1 g/L ofconditioning agent, 4 g/L ethoxylated linear alcohol non-ionicsurfactant, and sodium hydroxide or sulphuric acid to adjust the pH asnecessary.

-   -   1. Each copper-clad panel was immersed in CIRCUPOSIT™ MLB        Conditioner 211 solvent swell solution at 75° C. for 2 minutes,        then rinsed with flowing tap water for 2 minutes;    -   2. The panels were immersed in CIRCUPOSIT™ MLB Promoter 3308        permanganate solution at 80° C. for 3 minutes and then rinsed        with flowing tap water rinse for 2 minutes;    -   3. Each panel was immersed in an aqueous neutralizer solution of        3% sulfuric acid and 3% hydrogen peroxide at room temperature        for 1 minute followed by rinsing for 2 minutes with flowing tap        water;    -   4. The panels were then immersed in one of two conditioner        solutions: APTES at 60° C., and copolymer 2 in the table of        Example 1 at 60° C. for 90 seconds followed by rinsing with        flowing tap water for 2 minutes;    -   5. The panels were then etched with a solution of 1% sulfuric        acid and 75 g/L sodium persulfate at room temperature for 40        seconds followed by rinsing for 1 minute with DI water;    -   6. Each panel was immersed in an acidic pre-dip of 1% nitric        acid or 1 g/L potassium carbonate basic pre-dip at room        temperature for 30 seconds;    -   7. An aqueous ionic catalyst of 200 ppm palladium ions, 208 ppm        2,6-dimethylpyrazine and 1 g/L potassium carbonate with pH        adjusted to 9.5 using nitric acid was applied to the panels at        40° C. for 2 minutes followed by rinsing the panels with DI        water for 30 seconds;    -   8. Each panel was then immersed in a 0.25M sodium hypophosphite        reducing agent solution at 50° C. for 90 seconds followed by        rinsing with DI water for 20 seconds;    -   9. The panels were immersed in CIRCUPOSIT™ 4500 Electroless        Copper bath at 52° C. for 5 minutes to plate copper on the walls        of the through-holes of the panels;    -   10. After copper plating the panels were rinsed with flowing tap        water for 4 minutes.

Each panel was cross-sectioned nearest to the centers of thethrough-holes as possible to expose the copper plated walls. Thecross-sections, no more than 3 mm thick from the center of thethrough-holes, were taken from each panel to determine the through-holewall coverage. The European Backlight Grading Scale was used. Thecross-sections from each panel were placed under a conventional opticalmicroscope of 50× magnification with a light source behind the samples.The quality of the copper deposits was determined by the amount of lightvisible under the microscope that was transmitted through the sample.Transmitted light was only visible in areas of the plated through-holeswhere there was incomplete electroless coverage. If no light wastransmitted and the section appeared completely black, it was rated a 5on the backlight scale indicating complete copper coverage of thethrough-hole wall. If light passed through the entire section withoutany dark areas, this indicated that there was very little to no coppermetal deposition on the walls and the section was rated 0. If sectionshad some dark regions as well as light regions, they were rated between0 and 5. A minimum of ten through-holes were inspected and rated foreach board.

A backlight rating distribution graph showing the backlight performanceof the conditioners with the ionic catalyst for each plated panel isshown in FIG. 1. The plots in the graph indicate a 95% confidenceinterval for the backlight ratings of ten through-holes sectioned foreach board. The horizontal line through the middle of each plotindicates the average backlight value for each group of ten through-holesections measured. The conditioner which included copolymer 2 had theoverall best combination of through-hole wall coverage, ROP performanceand copper morphology.

Example 3

Comparison of electroless copper coverage on four-layer or eight-layercopper-clad test panels with a plurality of through-holes constructedfrom NP-175, 370HR, TUC-752, TUC-662, SY-1141, SY-1000-2, IT-158,NPG-150, and IT-180 laminate materials was done using the conditionersof copolymers 1-8 from the table in Example 1. The conditioner solutionswere prepared as described in Example 2. Each panel was 5 cm×12 cm andwas treated as follows: Each copper-clad panel was immersed inCIRCUPOSIT™ MLB Conditioner 211 solvent swell solution at 75° C. for 2minutes, then rinsed with flowing tap water for 2 minutes;

-   -   1. The panels were immersed in CIRCUPOSIT™ MLB Promoter 3308        permanganate solution at 80° C. for 3 minutes and then rinsed        with flowing tap water rinse for 2 minutes;    -   2. Each panel was immersed in an aqueous neutralizer solution of        3% sulfuric acid and 3% hydrogen peroxide at room temperature        for 1 minute followed by rinsing for 2 minutes with flowing tap        water;    -   3. The panels were then immersed in one of eight copolymer        conditioner solutions at 60° C. for 90 seconds followed by        rinsing with flowing tap water for 2 minutes;    -   4. The panels were then etched with a solution of 1% sulfuric        acid and 75 g/L sodium persulfate at room temperature for 40        seconds followed by rinsing for 1 minute with DI water;    -   5. Each panel was immersed in a 1 g/L potassium carbonate basic        pre-dip at room temperature for 30 seconds;    -   6. An aqueous ionic catalyst of 200 ppm palladium ions, 225 ppm        6-hydroxy-2,4-dimethylpyrimide and 1 g/L potassium carbonate        with pH adjusted to 9.5 using nitric acid was applied to the        panels at 40° C. for 2 minutes followed by rinsing the panels        with DI water for 30 seconds;    -   7. Each panel was then immersed in a 0.25M sodium hypophosphite        reducing agent solution at 50° C. for 90 seconds followed by        rinsing with DI water for 20 seconds;    -   8. The panels were immersed in CIRCUPOSIT™ 4500 Electroless        Copper bath at 52° C. for 5 minutes to plate copper on the walls        of the through-holes of the panels;    -   9. After copper plating the panels were rinsed with flowing tap        water for 4 minutes.

Morphology of each panel is shown in FIG. 2. Good to very slightly roughmorphologies were observed across all plated laminates. The panels wereexamined for ROP with a conventional optical microscope of 50×magnification.

Each panel was cross-sectioned nearest to the centers of thethrough-holes as possible to expose the copper plated walls as describedin Example 2. The European Backlight Grading Scale was used. Thecross-sections from each panel were placed under a conventional opticalmicroscope of 50× magnification with a light source behind the samples.The quality of the copper deposits was determined by the amount of lightvisible under the microscope that was transmitted through the sample asdescribed above in Example 2. FIG. 2 is a backlight rating distributiongraph showing the backlight performance of the conditioners with theionic catalyst for each plated panel. The plots in the graph indicate a95% confidence interval for the backlight ratings of ten through-holessectioned for each board. Although all of the copolymers had overallgood through-hole wall coverage, ROP performance and copper morphology,the conditioner which included copolymer 2 had the overall bestperformance.

1-9. (canceled)
 10. A method comprising: a) providing a substratecomprising a dielectric; b) contacting the substrate with a compositioncomprising a reaction product of one or more diglycidyl ether terminatedpolysiloxane compounds and one or more non-aromatic polyamines; c)applying a catalyst to the substrate and d) electrolessly plating metalon the substrate with an electroless metal plating bath.
 11. The methodof claim 10, wherein the catalyst is an ionic catalyst.
 12. The methodof claim 10, wherein the substrate further comprises a plurality ofthrough-holes, vias or combinations thereof.
 13. The method of claim 10,wherein the one or more diglycidyl ether terminated compounds have aformula:

wherein R₁, R₂, R₃, R₄, R₅ and R₆ may be the same or different and arechosen from hydrogen; linear or branched, substituted or unsubstituted(C₁-C₆)alkyl; m is an integer of 1 to 6, and n is an integer of 1 to 20.14. The method of claim 10, wherein the one or more non-aromaticpolyamines are chosen from aliphatic polyamines and alicyclicpolyamines.
 15. The method of claim 10, wherein the one or morenon-aromatic polyamines comprises a formula:

wherein R₇, R₈ and R₉ are independently chosen from hydrogen; linear orbranched, substituted or unsubstituted (C₁-C₁₀)alkylamine; linear orbranched, substituted or unsubstituted (C₁-C₁₀)alkyl; a moiety having ageneral formula:

wherein R₁₀ and R₁₅ are independently chosen from hydrogen; linear orbranched, substituted or unsubstituted (C₁-C₁₀)alkyl; linear orbranched, substituted or unsubstituted (C₁-C₁₀)alkylamine; and with theproviso that if the nitrogen atoms in compounds II and III are tertiary,at least one of R₇, R₈, and R₉ comprises substituent groups with two ormore primary nitrogen atoms, secondary nitrogen atoms, or a combinationof primary and secondary nitrogen atoms; and q, r and t may be the sameor different and are integers of 1 to
 10. 16. The method of claim 10,wherein the catalyst is a tin-palladium colloidal catalyst.
 17. Themethod of claim 10, wherein the composition further comprises one ormore additives chosen from water miscible organic solvents, surfactants,complexing agents and one or more pH adjusting agents.
 18. The method ofclaim 10, wherein the electroless metal plating bath is chosen from acopper, copper alloy, nickel and nickel alloy electroless metal platingbath.